Dấu \(.\)là dấu nhân
\(y+y.\frac{1}{4}:\frac{2}{7}+y:\frac{2}{9}=255\)
\(\Rightarrow y+y.\frac{1}{4}.\frac{7}{2}+y.\frac{9}{2}=255\)
\(\Rightarrow y+y.\frac{7}{8}+y.\frac{9}{2}=255\)
\(\Rightarrow y.\left(1+\frac{7}{8}+\frac{9}{2}\right)=255\)
\(\Rightarrow y.\left(\frac{8}{8}+\frac{7}{8}+\frac{36}{8}\right)=255\)
\(\Rightarrow y.\frac{51}{8}=255\)
\(\Rightarrow y=255:\frac{51}{8}\)
\(\Rightarrow y=255.\frac{8}{51}\)
\(\Rightarrow y=40\)
Vậy \(y=40\)
~ Ủng hộ nhé
\(y+y\cdot\frac{1}{4}:\frac{2}{7}+y:\frac{2}{9}=225\)
\(y+y\cdot\frac{1}{4}\cdot\frac{2}{7}+y\cdot\frac{9}{2}=225\)
\(y+y\cdot\frac{1}{14}+y\cdot\frac{9}{2}=225\)
\(y\cdot\left(1+\frac{1}{14}+\frac{9}{2}\right)=225\)
\(y\cdot\frac{39}{7}=225\)
\(y=225\cdot\frac{7}{39}\)
\(y=\frac{525}{13}\)
Dấu . là dấu nhân
y+y x 7/8 + y x 9/2 = 255
y x ( 1+ 7/8 + 9/2 ) = 255
y x 51/8 = 255
y = 255 : 51/8
y = 40
y+yx1/4:2/7+y:2/9=255
y+yx1/4x7/2+yx9/2=255
yx(1+1/4x7/2+9/2)=255
yx51/8=255
y=255:51/8
y=255x8/51
y=8
y + y x 1/4 x 7/2 + y x 9/2 = 255
y + y x 7/8 + y x 9/2 = 255
y x ( 1 + 7/8 + 9/2)=255
y x 51/8 = 255
y = 255 / (51/8)
y = 40
40 mới là đáp án đúng , ai được kq khác là sai rồi nhé !
\(y+y.\frac{1}{4}:\frac{2}{7}+y:\frac{2}{9}=255\)
\(y+y.\frac{7}{8}+y.\frac{9}{2}=255\)
\(y.\left(1+\frac{7}{8}+\frac{9}{2}\right)=255\)
\(y.\left(\frac{8}{8}+\frac{7}{8}+\frac{36}{8}\right)=255\)
\(y.\frac{51}{8}=255\)
\(y=255:\frac{51}{8}\)
\(y=255.\frac{8}{51}\)
\(y=\frac{3.17.5.8}{3.17}\)
\(y=40\)